Please help me understand!! Last night i was running my mill and all the sudden the tool holder came out of the spindle while it was roughing a part. It spun taper to taper before it overloaded..My spindle taper is trashed!! even worse the spindle is only a few months old. Can anybody tell me the most likely reason for this??
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Tools being thrown out of the spindle. HELP
- Thread starter jew745
- Start date
- Replies 28
- Views 5,856
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
What machine? What age? Had it been in hard service for a long time? Any crashes recently (besides this one)? What was the specific operation (speeds/feeds/cutting tool, W/DOC, work piece material)? Did the material lift during the cut?
Show us pics of the tool holder and pull stud.
Show us pics of the tool holder and pull stud.
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
When you get back to the machine (and if it can load tools normally), cycle through a few tools and see if they're seating correctly enough to test out the drawbar tension. I know the spindle is scored, but if a toolholder can seat firmly enough you can (carefully) take a big flat blade screwdriver or thin prybar and try to separate the toolholder flange from the spindle face. You can pad the lever with some thin sheets of Al or CU if you'd like, but you're trying to see if there's any issue with the belleville washers.
I don't know if this Mazak uses fingers or balls for actually gripping the pullstud, but by now they're likely trash anyway. Try to find any loose pieces that may have fallen out of the spindle during the failure, they may make clear what happened.
You'll either need a tech to pull the spindle if it's trashed, or if you're ambitious you can try to do the work yourself. I suggest getting some pics up the spindle bore and of the pull stud and emailing them to your Mazak service people on Monday.
I don't know if this Mazak uses fingers or balls for actually gripping the pullstud, but by now they're likely trash anyway. Try to find any loose pieces that may have fallen out of the spindle during the failure, they may make clear what happened.
You'll either need a tech to pull the spindle if it's trashed, or if you're ambitious you can try to do the work yourself. I suggest getting some pics up the spindle bore and of the pull stud and emailing them to your Mazak service people on Monday.
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
Also, we had another member whose Mazak was tossing tools from its spindle a year or so back. This is a long thread but it might have info that could help you: http://www.practicalmachinist.com/vb/mazak/do-tools-fall-out-spindle-276224/
Dave K
Diamond
- Joined
- Mar 21, 2004
- Location
- Waukesha, WI
I'm confused how the taper can spin to destroy the spindle. Aren't there drive keys on the spindle face that would prevent this?
Nerdlinger
Stainless
- Joined
- Aug 10, 2013
- Location
- Chicago, IL
In my experience the tool will continue to spin and dance around for just a little bit from its own momentum but it's enough to do plenty of damage. I had a tool holder pull out from poor part clamping. Poor work holding = end mill chatter = hard rhythmic pulling on the end mill = tool holder gets pulled out. That was on a small 30 taper machine though. If you have poor runout make sure to look into whether or not the spindle/bearings are actually bent or if it is just the gouges in the spindle taper keeping your tool holde from seating correctly that may need to be ground down. I recently had this happen to me. Tool runout was .0015 but inside of spindle taper was right on. Used some 320 grit sandpaper on a small spot near the top of the taper where I felt some scratches just to knock off the high points and now we're good...a lot cheaper than replacing a whole spindle!
Stuart Caruk
Stainless
- Joined
- Feb 20, 2007
- Location
- Ridgefield, WA
I had a wreck with a VMC a couple years back. Busted an insert on a facemill going 140IPM, which busted off the other inserts and tried to literally rip the toolholder out of the spindle. The impact sheared both drive keys and spun the tool, welding it to the spindle. Took a bit of work to get the tool out, and I had a guy come in and regrind the spindle, as well as another spindle while he was here. Both machines are still very accurate and I'm happy. It cost around $1200 to have both spindles ground in place FWIW.
Nerdlinger
Stainless
- Joined
- Aug 10, 2013
- Location
- Chicago, IL
Did they regrind it on site? Do you know if they can regrind a dual-contact spindle?
Yes, they do it on site. Yes, they can do dual contact!
Spindle Grinding Service, Inc. — Have Grinder, Will Travel — Grinding spindle tapers in the machine" with on-site, in-plant, mobile, precision grinding equipment to reduce downtime, runout and teardown
techie1961
Plastic
- Joined
- Jan 18, 2009
- Location
- Pickering, Ontario, Canada
Roughing cutters tend to want to come out of their holder. I admit that I know virtually nothing about your machine, the type of holder etc. but I am a tool and die maker that has a lot of milling experience. Due to the helix of a roughing cutter and the type of cut, there is a very strong extraction force. I've seen many mill tables that have had paths cut into them as the cutter slipped out and it wasn't noticed. Either a Weldon shank or threaded was the only way to truly hold them in.
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
The OP says in post #3 that the roughing was moderate, and this was the holder coming out of the spindle, not a tool slipping from the toolholder. Doesn't sound like the issue to me...
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
Good luck with that (seriously). It was the other Mazak thread that made me unlikely to ever buy one of their products, and a lot of that was the poor customer response from Mazak and their reps. I hope you get help from them, but be prepared to fight for it.
Looking forward to some pics tomorrow.
Stuart Caruk
Stainless
- Joined
- Feb 20, 2007
- Location
- Ridgefield, WA
Tearing up a spindle is not a warranty issue, so I wouldn't expect any help from them unless the spindle itself was defective.
In my case I got off easy. The spindle was reground on site. Frank works out of Bend Oregon, so the travel time was pretty minimal. As I recall he stopped by on the return from another trip and gave me a break on the travel time. I'm quite happy. He can grind a dual contact spindle as well, but he can also grind a taper with a relief in the center section so the toolholder can only contact at either end of the holder. I had him do this on our dual contact spindle and I'm very happy with it. I get performance similar to a dual contact and I can use any toolholder.
1. Certified Spindle Repair, Inc.
P.O. Box 6449
Bend, OR 97708
541-389-4120
541-948-1296
Frank Brian
In my case I got off easy. The spindle was reground on site. Frank works out of Bend Oregon, so the travel time was pretty minimal. As I recall he stopped by on the return from another trip and gave me a break on the travel time. I'm quite happy. He can grind a dual contact spindle as well, but he can also grind a taper with a relief in the center section so the toolholder can only contact at either end of the holder. I had him do this on our dual contact spindle and I'm very happy with it. I get performance similar to a dual contact and I can use any toolholder.
1. Certified Spindle Repair, Inc.
P.O. Box 6449
Bend, OR 97708
541-389-4120
541-948-1296
Frank Brian
Rstewart
Stainless
- Joined
- Jun 14, 2006
- Location
- Huntsville Alabama
I bet that made quite the noise.... You have to clean out your britches?
fmari --MariTool-
Titanium
- Joined
- Nov 15, 2005
- Location
- Illinois
If you need to get up and running ( who doesn't) bore it with a carbide shanked boring bar with a CBN insert. Before MariTool and I was a programmer I did it to my 40 taper and 30 taper mills if we ever had a crash and lost a tool. Not for beginners but if done properly you can get great results. But my first choice would be to call a pro and have him grind it. But some people dont have this option.
Can someone put a link to that thread when I bored out that spindle?
Can someone put a link to that thread when I bored out that spindle?
